Legos. (And not just a single, focused kit, in isolation.) You inevitably start designing/building/designing (a chicken and egg perspective) your own construc

Legos. (And not just a single, focused kit, in isolation.) You inevitably start designing/building/designing (a chicken and egg perspective) your own constructs. You can do it together with others including peers. And it provides strong stimulation in 3D (and even 4D -- zoom... crash!) perspective.